Photographic objective particularly for supermicrofilm

ABSTRACT

A photographic objective particularly adapted for use during exposure or projection of supermicrofilm. The objective has a viewing angle on the order of + OR - 12* with a relatively large aperture having an F-number of 1.4, the magnification being on the order of 1/100. At the same time the objective has highly favorable aberration conditions and is well-suited to be used with supermicrofilm.

1 United Kazamaki et a].

[75] Inventors: Tomokazu Kazamaki; Koichi Kobayashi, both of Tokyo,Japan [73] Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo-to,Japan [22] Filed: July 3, I972 [21) Appl. No.: 268,472

[30] Foreign Application Priority Data [4 June 18, 1974 3,551,030l2/l970 Gilkeson et al 350/2l4 X Primary Examiner-John K. CorbinAttorney, Agent, or Firm-Steinberg & Blake 5 7] ABSTRACT A photographicobjective particularly adapted for use during exposure or projection ofsupermicrofilm. The

July 9. 197] Japan 46-50884 ob ective has a viewing angle on the orderof il2 52 us. Cl. 350/214, 350/214 with a relatively large aperturehaving F-humher of 51 Int. Cl. G02b 9/64 the meghifieetieh being theOrder of At 58 Field of Search 350/214, 176 the same time the Objectivehas highly favorable abetration conditions and is well-suited to be usedwith [56] References Cited supehhterofilm- UNITED STATES PATENTS3,506,340 4/1970 Kinoshita 350/214 2 Claims, l0 Drawing Figures 6 L1 L8L9 L10 L L5 L; 3

PATENTEUJUN 1a 1914 3317x502 sum 2 OF 2 Sine Condit oh Chroma icDistortion Asii ma ism SPhmmL erration Aberration Abermflon BACKGROUNDOF THE INVENTION The present invention relates to photographicobjectives.

In particular, the present invention relates to that type of objectivewhich is used either in order to expose or in order to projectsuperrnicrofilm.

Conventional objectives of this type generally have a viewing angleranging from approximately i3 to about :6" and they have a magnificationof at least approximately l/30, the objective when used as a projectinglens having a magnification which is not larger than 30.

, However, conventional objectives of this type are difficult to designwith good aberration characteristics, and in addition it is difficult toprovide for objectives of this type a relatively large aperture.Moreover, although a magnification of substantially less than 1/30 isdesirable, such a range of magnification has not yet been achieved withconventional objectives of this type.

SUMMARY OF THE INVENTION It is accordingly a primary object of thepresent invention to provide a photographic objective which will avoidthe above problems.

In particular, it is an object of the invention to provide aphotographic objective which will have a relatively large aperture suchas an aperture having an F- number of 1.4.

Also it is an object of the present invention to provide a photographicobjective of the above type which has a magnification on the order of l/100.

In addition, it is an object of the present invention, while maintainingthe latter characteristics, to still provide an objective having highlyfavorable aberration characteristics.

Thus, it is especially an object of the present invention to provide aphotographic objective which is particularly well suited for exposing orprojecting supermicrofilm.

Thus, in accordance with the present invention there is provided aphotographic objective to be used during exposure or projection ofsupermicrofilm, and this objective has at least nine lenses designatedfrom front to rear as L, L respectively, with lenses L and L having acommon surface of radius r,, and with lenses L, and L having a commonsurface of radius r,,. with the objective according to one embodimentterminating at its rear in a cover glass, which is not used in a secondembodiment of the invention, and with the objective of the inventionhaving in the embodiment with the cover glass the data of Table I,below, and in the embodiment without the cover glass the data of TableIII set forth below.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way ofexample in the accompanying drawings which form part of this appli- Ycation and in which:

FIGS. 2A-2D respectively illustrate graphically various characteristicsof the objective of FIG. 1;

FIG. 3 is a schematic representation of a second enibodiment of aphotographic objective according to the invention; and

FIGS. 4A4D respectively illustrate graphically chai acteristics of theobjective of FIG. 3;

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, the embodimentof an objective according to the invention which is illustrated thereinincludes ten lenses designated from front to rear as L,- L,,,,respectively. Starting with the front lens which is directed toward thelarger conjugate, the first lens L, is a negative lens, while the secondlens L is a biconvex position lens spaced by considerable distance alongthe principal axis from the first lensL,. The third lens L, is apositive meniscus lens. The lenses L,-L,, have the front and rearsurfaces illustrated. Thus, L, has the front surface 1 and rear surface2, lens L has the front surface 3 and rear surface 4, and lens L hasfront surface 5 and rear surface 6. i

The fourth and fifth lenses L4 and L directly contact each other attheir common surface 8 where they are cemented together, the lens L,having the front surface 7 while the lens L has the rear surface 9.These aircontacting refractive surfaces 7 and 9 of the joined lenses L,and L are both convex with respect to the first lens L,.

The objective of FIG. 1 includes a sixth lens L, which is a biconcavenegative lens and a seventh lens L, which is a positive lens cementeddirectly to the lens L so that these lenses have a common surface 11with the lens L having an exposed front surface 10 while the lens L hasan exposed rear surface 12.

The eighth lens L is a positive lens, while the ninth lens L is also apositive lens.

At the rear of all of these lens elements the objective of FIG. 1 isprovided with a cover glass L which is optional.

With this particular objective of FIG. 1 it is possible to provide ahigh resolution with an F-number of 1.4 and a viewing angle of 24.

The objective of FIG. 1 satisfies the following conditions: I

where, f focal length of the entire optical system,

r,,, r,,,, r,, are respectively equal to the radii of curvature ofrefractive surfaces 9-11, respectively,

n,,,, n,, are respectively equal to the d-Iine refractive indices of thelenses L and L [3,, and B1 are respectively the power of the partialoptical system situated in front of refractive surfaces 12 and 14, theentire system being assumed to have a power of one or unity.

Referring to the above conditions, the condition (1) takes care of thesituation where an insufficiently corrected high order of sphericalaberration will be treated in asatisfactory manner at the refractivesurface 11,

which is the common surface between the joined lenses 3 lute quantity ofspherical aberration can be reduced over the full aperture range- In theevent that n n or in other words the difference between the refractiveindices on both sides of the common surface 11 between the lenses La andL is less than 0.03 and the radius of curvature r of refractive surface11 is greater than 0.70f, then the extent to which correction is madefor higher order spherical aberration is far too small and is withouteffect. On the other hand, when n n is greater than 0.1 and r is lessthan 0.37f, both the higher order spherical aberration as well as thelower order spherical aberration will be increased at the surface 11.Therefore, it will not be possible to correct the peripheral sphericalaberration by the use of other lens elements, or otherwise the positive,annular spherical aberration will reach a large value which will lead toa reduction in the resolution of the image.

As may be seen from condition (2) when r is less than 0.3f there will bean increase in the higher order coma aberration, while when the value ofr; is greater than 0.4f, astigmatism will be corrected to a lesserextent, so that it will be difficult to maintain a balance in the totalof the aberrations.

As may further be seen from condition (2) when the value of r is lessthan 0.50f, the extent of coma aberration and, particularly, sagittalcoma will become too great to be acceptable, while if r is greater thanl.8f, then the Petzval sum will be undesirably increased and the backfocus will be reduced.

Condition (3) is provided in order to correct astigmatism which developsin order to compensate the coma aberration correction carried out inaccordance with condition (2). In a conventional system a. valuecorresponding to B is selected in such a way as to be negative. However,according to the present invention the value B is positive, and the sameis true of [3 These values 12 and B are selected in this way so as tobecome effective in making the astigmatism coefficient provided by eachof the immediately subsequent positive lenses negative or almost zero.On the other hand, when B12 and Bi, are both less than 0.10 and 0.40,respectively, it is not possible to correct the astigmatism, while whenboth B and B are greater than 0.42 and 0.86, respectively, correctionfor spherical aberration will not be sufficient.

Thus, it is a characteristic of the present invention that it enablescoma aberration to be corrected by increasing the radius of curvature asset forth above, while preventing an increase in the Petzval sum bysituating the negative first lens L, at a large distance from thesucceeding elements. In addition, with the present invention it ispossible to increase the peripheral light quantity by making use of thepupil aberration of the first negative lens.

Specific embodiments of the invention are set forth in the tables whichfollow. in Table I which follows, the several lenses of HO. 1 aredesignated in sequence in the first column, while the radii of curvatureof the several lens surfaces of FIG. 1 are set forth in the secondcolumn, with the thicknesses of the several lens elements beingindicated by t with a suitable subscript and the distance from one lensto the next is designated by d with a suitable subscript. In the glassconstants, the column designated n represents the refractive index forthe particular lens at the d-line, while the last column y representsthe Abbe number.

TABLE I Aperture Focal Length=l00mm Ratio Glass Constants Lens l:l.4

r,=+545.33 mm L 1,=|2.50mm 1.5 I633 64.1

r,=+l48.66 mm d,=77.5lmm r l-382.34 mm L, !,=20.00mm l.77250 49.6

r =423.95 mm d =l.25mm r =+l l9.l6 mm L; =20.00mm 1.77250 49.6

r,-=+222.00 mm d,=l.25mm re l-59.6] mm L l =22.00mrn l.77250 49.6

rg=+l04.63 mm L l =l4.38mm 1.80518 25.5

r,=+35.28 mm d =l8.75mm r =-l44.4lmm L !.--l5.00mm 1.7215! 29.3

r ='+4l.72 mm L !-1=20.00mm [.80400 46.6

r,,=-8l3.93 mm d- ,=l.25mm r =+279.35111m L =l9.00mm l.8l554 44.4

r, =l83.49mm

d =l.25mm r,,=+72.88 mm L, t =l8.l3mm l.80440 39.6

r,,=+l22.05 mm d1=7.S0mm r, L l =40.00mm 1.52600 58.8

(image surface) Thus, the above Table 1 provides data for a specificembodiment of an objective which is illustrated in FIG. 1. Table llwhich follows is a Table of von Seidel coefficients for the embodimentof FIG. 1 which has the data of Table 1 above. in Table ll thesuccessive surfaces of the successive lenses are designated in the firstcolumn.

The position of the object is 89.4f, the position of the entrance pupilis 1.58f, and the magnification is 1/90. The column S, designatesspherical aberration, the column S designates coma aberration, thecolumn 8;, designates astigmatism, the column P designates the Petzvalcoefficient, and the column 8; designates distortion aberration.

TABLE ll von Se1del Coefiic1ents Surface 51 S, S; P S5 .SUM 0010 +00030042 +0176 +0.63)

therein show curves corresponding to the various aberrations. Thus, thegraph of FIG.- 2A shows the curves for the sine condition, which is thesolid line curve and the spherical aberration which is the dotted linecurve. It will be noted that these aberrations are maintainedexceedingly small.

The second graph of FIG. 28 illustrates the chromatic aberration for theembodiment of FIG. 1 along the d-line, which corresponds to the solidline curve of the second graph of FIG. 2 and the c-line which isrepresented by the dotted line curve of FIG. 28. It will be noted thatthese aberrations also are maintained within acceptable valves.

The same is true of the distortion aberration shown in FIG. 2C and theastigmatism shown for AS with the solid line in the graph of FIG. 2D andfor AM with the dotted line in the graph of FIG. 2.

In the embodiment of the invention which is illustrated in FIG. 3, thecover glass at the rear of the objective is omitted. The remaininglenses have the same general arrangement as is the case with FIG. 1, asis apparent from comparing FIG. 3 with FIG. 1, although the lenses aredifferent in their actual specific characteristics. The specificembodiment of FIG. 3 has the data shown below in Table 111. Thus, inTable III which follows to provide specific data for the embodiment ofFIG. 3, the first column designates the several lenses L L respectively,while the radii of curvature of the successive lens surfaces aredesignated in the second column. The third column designates on the onehand the thickness of the successive lenses along the principal axis,this thickness being designated by t with a suitable subscript. whilethe distance from one lens to the next is designated by d with asuitable subscript. The glass constants are designated in the last twocolumns with the refractive index n being along the d-line while thelast column v designates the Abbe number of the glass.

TABLE III Aperture Focal Length 100 mm Ratio Glass Constants Lens 1:1.4

r,=+521.24 mm L l,=l2.46mm 1.51112 60.5

r,=l-l40.57 mm d,=77.28mm r;,=+223.45 mm L, !,=l9.94mm 1.77250 49.6

r =480.98 mm d l .25mm r,= +l0l.5l mm L, l =19.94mm 1.77250 49.6

r =+l60.04 mm d,=l.25mm r =+63.27 mm L, t =24.43mm 1.77250 49.6

r,=+l32.50 mm L, t,=l4.33mm 1.80518 25.5

r,=+32.39 mm d,=l5.58mm r, "79.20 mm L, =l4.96mm 1.72151 29.3

r, =l-43.39 mm =l9.94mm 1.80400 46.6 r,,=259.l5 mm di=l .25mm r =+191.36mm L, 1,.=l8.95mm 1.80400 46.6

r ,=384.24 mm d,=l.25mm l-85.76 mm L, l.=l7.4$mm 1.83400 37.2

-Hssmi mm The von Seidel coeflicients for the embodiment of FIG. 3 areset forth in Table IV which follows below. Thus, in Table IV thesuccessive lens surfaces are designated in the first column while thevarious headings at the successivecolumns have the same significance asin the case of Table 11 above. In Table IV, the position of the objectis 89.2f, the position of the entrance pupil is 1.15f, and themagnification is 1/90.

Surface 1 +0.002 +0.006 +0.023 +0.065 +0308 2 0.278 +0.126 ().057 -0.241+0.135 3 +0.237 +0.050 +0.010 +0.195 +0043 4 +0.107 0144 +0.553 +0.09ll.459 5 +0046 +0.013 +0.004 +0.42) +0.126 6 +0.002 0.026 +0.356 0.2721.l40 7 0.076 0.034 0.015 +0.689 +0302 8 0.0l2 +0.021 0.040 +0.008 H10609 0.099 0.099 0.099 l .377 l .469 10 0.339 +0.497 0.728 0.529 +1.844 11+0.0S6 +0.087 +0.136 +0.06l +0.307 l2 +0.029 0.092 +0.295' +0.172 l .49613 +0.000 +0.005 -0.276 +0.233 +2.25) 14 +0.094 -0.l62 +0.277 +0.1l60.637 15 0.001 +0.024 0.596 +0.530 +1.598 16 +0.21) 0.l76 +0.142 0.0250.094

SUM 0.012 0.002 --0.0l5 +0.145 +0.65]

The aberration curves of the embodiment of FIG. 3 are illustrated inFIGS. 4A-4D. The several curves of the graphs of FIGS. 4A-4D correspondto the curves shown in FIGS. 2A-2D for the embodiment of FIG. 1. Thus inthe graph of FIG. 4A the sine condition and spherical aberration curvesare respectively designated for the embodiment of FIG. 3 with thesolidand dotted lines, in FIG. 4B the chromatic aberration curves arerepresented with the solid curve representing the chromatic aberrationalong the small d-Iine while the dotted line curve represents thechromatic aberration along the small c-line. The distortion aberrationis illustrated in FIG. 4D, while the two astigmatism curves of FIG. 4Dcorrespond to those of FIG. 2, and it becomes apparent from FIG. 4D thatthe astigmatism with the embodiment of FIG. 3 is improved over that ofFIG. 1 whereas the remaining aberrations are if anything also improvedover that of FIG. 1, so that the embodiment of FIG. 3 without the rearcover glass achieves the objects of the invention with even lessdistortion and aberration than is the case with the embodiment of FIG.1.

The aberration curves illustrated in FIGS. 2A-2D and FIGS. 4A-4D areobtained in the case of F=l00.

What is claimed is:

l. A photographic objective to be used during exposure or projection ofsuperrnicrofilm, said objective having from front to rear a series of 10lenses L,-L of which the rear lens L is acover glass, with lenses L andL having a common surface of radius r; and with lenses L and L having acommon surface of radius r wherein for a focal length of mm and for anaperture ratio of 1:1.4, the objective has the data of the followingTable I, in which the radii of curvature of the sequential lens surfacesare set forth in the second column, with the thickness of the severallens elements being indicated by t and the distance from one lens to thenext by d, and the glass constants n representing the refractive indexat the d-line while v represents the Abbe number:

TABLE 1 Aperture Focal Length-100mm Ratio Glass Constants Lens 1:1.4

r 1-545.33 mm L, 1,=l2.50mm 1.51633 64.1

r,=+148.66 mm d,=77.51mm r,=+382.34 mm L, !,=20.00mm 1.77250 496 r=-423.95 mrn d =1.25mm r,=l-'l 19.16 mm L, !,=20.00mm 1.77250 49.6

r ='+-222.OO mm d =1.25mm

r,=+59.6l mm L. =22.00mm 1.77250 49.6

r.,=+l04.63 mm L, l =l4.38mm 1.80518 25.5

r,=+35.28 mm d =18.75mm r, =l44.41mm L. I lSDOmm 1.72151 29.3

r =+41.72 mm L, t =20.00mm 1.80400 46.6

r,,--8l3.93 mm d,=1.25mm r,,=+279.35mm L =l9.00mm 1.81554 44.4

r, =-183.49mm

d =1.25mm r, +72.88 mm L, i,=18.l3mm 1.80400 39.6

r,,=+122.05 mm d =7.50mm 11 L =40.00mm 1.52600 58.8

fil

(image surface) 2. A photographic objective to be used during exposureor projection of supermicrofilm, said objective having from front torear nine lenses designated L -L wherein lenses L and L are cementedtogether and have a common surface of radius r, while lenses 1.. and Lare cemented together and have a common surface of radius r wherein fora focal length of mm for the entire lens system and an aperture ratio of1:14, the objective has the data of the following Table 111, in whichthe second column designates the radii of curva ture of the successivelens surfaces, the third column designates the thicknesses t of thesuccessive lenses and the distance d therebetween while the glassconstants in the last two columns are designated n for the refractiveindex along the d-line and v for the Abbe number:

TABLE I11 Aperture Focal Length=l00 mm Ratio Glass Constants 1:1.4 Lensn v r,=+521.24 mm L, l =l2.46mm 1.51112 60.5

r,=+140.57 mm d =77.28mm r,= l-223.45 mm L; l =l9.94mm 1.77250 49.6

ra -480.98 mm d,=l.25mm r,=+l0l.51 mm L, l =l9.94mm 1.77250 49.6

r +l60.04 mm d =l.25mrn r =+63.27 mm L t,=24.43mm 1.77250 49.6

r =+132i5O mm L; !F 14.33mm 1.80518 25.5

r =+32.39 mm d.=15.58mm r =79.20 mm L, l =l4.96mm 1.72151 29.3

r ,=+43.39 mm L, t =l9.94mm 1.80400 46.6

r,,=259.15 mm d,=l.25mm r,;=+l9l.36 mm L I !,,=l8.95mm 1.80400 46.6

r -384.24 mm 1 d LZSmm r, =+85.76 mm L 1,=17.45mm 1.83400 37.2

r,,=+-l836.31 mm

1. A photographic objective to be used during exposure or projection ofsupermicrofilm, said objective having from front to rear a series of 10lenses L1-L10, of which the rear lens L10 is a cover glass, with lensesL4 and L5 having a common surface of radius r8 and with lenses L6 and L7having a common surface of radius r11, wherein for a focal length of 100mm and for an aperture ratio of 1:1.4, the objective has the data of thefollowing Table I, in which the radii of curvature of the sequentiallens surfaces are set forth in the second column, with the thickness ofthe several lens elements being indicated by t and the distance from onelens to the next by d, and the glass constants n representing therefractive index at the d-line while v represents the Abbe number: TABLEI Aperture Focal Length 100mm Ratio Glass Constants Lens 1:1.4 n v r1+545.33 mm L1 t1 12.50mm 1.51633 64.1 r2 +148.66 mm d1 77.51mm r3+382.34 mm L2 t2 20.00mm 1.77250 49.6 r4 -423.95 mm d2 1.25mm r5 +119.16mm L3 t3 20.00mm 1.77250 49.6 r6 +222.00 mmd3 1.25mmr7 +59.61 mm L4 t422.00mm 1.77250 49.6 r8 +104.63 mm L5 t5 14.38mm 1.80518 25.5 r9 +35.28mmd4 18.75mmr10 -144.41mm L6 t6 15.00mm 1.72151 29.3 r11 +41.72 mm L7 t720.00mm 1.80400 46.6 r12 -813.93 mmd5 1.25mmr13 +279.35mm L8 t8 19.00mm1.81554 44.4 r14 -183.49mm d6 1.25mm r15 +72.88 mm L9 t9 18.13mm 1.8040039.6 r16 +122.05 mm d7 7.50mm r17 infinity L10 t10 40.00mm 1.52600 58.8r18 infinity (image surface)
 2. A photographic objective to be usedduring exposure or projection of supermicrofilm, said objective havingfrom front to rear nine lenses designated L1-L9, wherein lenses L4 andL5 are cemented together and have a common surface of radius r8 whilelenses L6 and L7 are cemented together and have a common surface ofradius r11, wherein for a focal length of 100 mm for the entire lenssystem and an aperture ratio of 1:1.4, the objective has the data of thefollowing Table III, in which the second column designates the radii ofcurvature of the successive lens surfaces, the third column designatesthe thicknesses t of the successive lenses and the distance dtherebetween while the glass constants in the last two columns aredesignated n for the refractive index along the d-line and v for theAbbe number: TABLE III Aperture Focal Length 100 mm Ratio GlassConstants 1: 1.4 Lens n v r1 +521.24 mm L1 t1 12.46mm 1.51112 60.5 r2+140.57 mm d1 77.28mm r3 +223.45 mm L2 t2 19.94mm 1.77250 49.6 r4-480.98 mm d2 1.25mm r5 +101.51 mm L3 t3 19.94mm 1.77250 49.6 r6 +160.04mm d3 1.25mm r7 +63.27 mm L4 t4 24.43mm 1.77250 49.6 r8 +132.50 mm L5 t514.33mm 1.80518 25.5 r9 +32.39 mm d4 15.58mm r10 -79.20 mm L6 t6 14.96mm1.72151 29.3 r11 +43.39 mm L7 t7 19.94mm 1.80400 46.6 r12 -259.15 mm d51.25mm r13 +191.36 mm L8 t8 18.95mm 1.80400 46.6 r14 -384.24 mm d61.25mm r15 +85.76 mm L9 t9 17.45mm 1.83400 37.2 r16 +1836.31 mm